[PATCH v2 06/10] engines/libblkio: Add option libblkio_write_zeroes_on_trim

[Alberto Faria <afaria@redhat.com>]

When set, trim IOs will be submitted as blkioq_write_zeroes() requests
instead of blkioq_discard() requests.

Signed-off-by: Alberto Faria <afaria@redhat.com>
---
 HOWTO.rst          |  4 ++++
 engines/libblkio.c | 20 ++++++++++++++++++--
 fio.1              |  3 +++
 3 files changed, 25 insertions(+), 2 deletions(-)

diff --git a/HOWTO.rst b/HOWTO.rst
index f77d76cc..273b7a68 100644
--- a/HOWTO.rst
+++ b/HOWTO.rst
@@ -2891,6 +2891,10 @@ with the caveat that when used on the command line, they must come after the
 
 	Submit vectored read and write requests.
 
+.. option:: libblkio_write_zeroes_on_trim : [libblkio]
+
+	Submit trims as "write zeroes" requests instead of discard requests.
+
 I/O depth
 ~~~~~~~~~
 
diff --git a/engines/libblkio.c b/engines/libblkio.c
index 219bb0dc..66a9bd31 100644
--- a/engines/libblkio.c
+++ b/engines/libblkio.c
@@ -41,6 +41,7 @@ struct fio_blkio_options {
 
 	unsigned int hipri;
 	unsigned int vectored;
+	unsigned int write_zeroes_on_trim;
 };
 
 static struct fio_option options[] = {
@@ -89,6 +90,16 @@ static struct fio_option options[] = {
 		.category = FIO_OPT_C_ENGINE,
 		.group	= FIO_OPT_G_LIBBLKIO,
 	},
+	{
+		.name	= "libblkio_write_zeroes_on_trim",
+		.lname	= "Use blkioq_write_zeroes() for TRIM",
+		.type	= FIO_OPT_STR_SET,
+		.off1	= offsetof(struct fio_blkio_options,
+				   write_zeroes_on_trim),
+		.help	= "Use blkioq_write_zeroes() for TRIM instead of blkioq_discard()",
+		.category = FIO_OPT_C_ENGINE,
+		.group	= FIO_OPT_G_LIBBLKIO,
+	},
 	{
 		.name = NULL,
 	},
@@ -455,8 +466,13 @@ static enum fio_q_status fio_blkio_queue(struct thread_data *td,
 			}
 			break;
 		case DDIR_TRIM:
-			blkioq_discard(data->q, io_u->offset, io_u->xfer_buflen,
-				       io_u, 0);
+			if (options->write_zeroes_on_trim) {
+				blkioq_write_zeroes(data->q, io_u->offset,
+						    io_u->xfer_buflen, io_u, 0);
+			} else {
+				blkioq_discard(data->q, io_u->offset,
+					       io_u->xfer_buflen, io_u, 0);
+			}
 		        break;
 		case DDIR_SYNC:
 		case DDIR_DATASYNC:
diff --git a/fio.1 b/fio.1
index 9b8995b5..ad061caa 100644
--- a/fio.1
+++ b/fio.1
@@ -2637,6 +2637,9 @@ Use poll queues.
 .TP
 .BI (libblkio)libblkio_vectored
 Submit vectored read and write requests.
+.TP
+.BI (libblkio)libblkio_write_zeroes_on_trim
+Submit trims as "write zeroes" requests instead of discard requests.
 .SS "I/O depth"
 .TP
 .BI iodepth \fR=\fPint
-- 
2.38.1